Whether imported rotary vane vacuum pump or imported reciprocating vacuum pump, vacuum valve is a very important component, it has a great impact on the reliability and economy of the operation of imported vacuum pump. The designed valve not only has long service life, reliable operation, but also has small resistance loss. The flow resistance loss of the poorly designed valve can reach more than 15% of the shaft power, and the service life is short, and the operation reliability is poor. The valve of the imported vacuum pump is very similar to that of the volumetric compressor. At present, the valve design of the compressor is quite mature, and some research results can be applied to the valve design of the vacuum pump.
Taking the inlet vacuum valve of reciprocating vacuum pump as an example, the motion rule of the valve disc is discussed. When the piston moves to a fixed position, the pressure difference between the two sides of the valve slice exceeds the valve spring force, and the valve slice starts to start until it collides with the lift limiter. A slight rebound occurs. The valve slice then pushes down the air flow, changes direction again, returns to the lift limiter, and holds for a period of time until the piston connects. When the motion speed decreases near the stop point, the gas pressure difference between the cylinder and the cylinder decreases, and the valve spring force exceeds the thrust of the air flow to the valve plate, the valve disc opens and closes until it finally lands on the valve seat.
DDC-JQ-B Series Electro-Magnetic Vacuum Gas Valve
If the main parameters of the valve are unreasonable or the operating conditions are far from the design conditions, the spring force of the valve will be too large or too small. The former causes valve flutter and the latter delays valve closure, which not only affects the economy of the vacuum pump, but also greatly reduces the life of the valve.
|Valve Leakage Rate(Pa.L/S)||＜6.7×10-4|
|Applicable temperature (℃)||-25～+50|
|Winding temperature (℃)||≤65|
|Time for opening and closing the valve (S)||≤3|
|Rated voltage (V/Hz)||220±10%/50|
|Model||Nominal Diameter(DN)||ΦW||ΦD||ΦB||H||A||n-d||Flange standard|
In order to design the valve with reasonable valve disc motion law, the mathematical model of valve disc motion law of vacuum pump was established. The actual intake and exhaust process is quite complex, so we should make an appropriate simplification.
1. the intake and exhaust process is very short and can be regarded as adiabatic process.
2. the gas state is generally less than the normal pressure, and the pressure is smaller. It can be regarded as an ideal gas and the specific heat is fixed value.
3. There is no pressure pulsation in the valve chamber.
4. The valve plate is only used for translation of single degree of freedom, and the movement of each ring is synchronized when multi-ring.